WO2024003996A1

WO2024003996A1 - Wireless communication system, wireless communication method, and wireless station

Info

Publication number: WO2024003996A1
Application number: PCT/JP2022/025619
Authority: WO
Inventors: 耕一原田; 順一阿部; 史洋山下
Original assignee: 日本電信電話株式会社
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2024-01-04

Abstract

A wireless communication system according to this embodiment is characterized by comprising: a weather radar antenna that is provided to a wireless station and transmits a signal from the wireless station to a node station and receives a reflected weather radar signal; a rainfall amount prediction unit that predicts the amount of rainfall between the wireless station and the node station on the basis of the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station on the basis of the amount of rainfall predicted by the rainfall amount prediction unit; and a switching control unit that, when the quality of wireless communication predicted by the quality prediction unit is lower than a predetermined threshold value, controls switching of a line connecting the node station and the wireless station to another line connecting the node station and another communication station before the line is disconnected.

Description

Wireless communication system, wireless communication method and wireless station

The present invention relates to a wireless communication system, a wireless communication method, and a wireless station.

In recent years, mobile communication systems have developed and it has become possible to enjoy mobile services over most parts of the earth. Additionally, one of the requirements for the 5th generation (Beyond 5G) or 6th generation mobile communication systems that are expected to be commercialized in the future is ultra-coverage.

Super coverage refers to expanding the service area to places where it is expensive to install existing base stations or where it is difficult to install base stations, such as in the mountains, at sea, and in the air. There is also a need to strengthen national resilience against natural disasters, and it is hoped that a communication system that can withstand ground disasters will emerge.

In order to realize such a wireless communication system, geostationary satellites, medium earth orbit satellites (MEO), low earth orbit satellites (LEO), high altitude pseudosatellites (HAPS), Unmanned aerial vehicles (UAVs) and non-terrestrial networks (NTNs) using drones and other devices are attracting attention.

In the NTN, the above-mentioned satellites, HAPS, etc. connect communication links to each other to form a network, and are further connected to a terrestrial mobile network via a terrestrial base station. Satellites and HAPS are equipped with mobile base station functionality.

The communication line in HAPS consists of a feeder link (FL) between HAPS and a terrestrial gateway station (ground station) on the terrestrial communication network side, and a service link (SL) between a communication relay device and a terminal. There is. For example, HAPS is located at an altitude of approximately 20 km, and the ground area (cell) radius is approximately 50 km. The HAPS service link is expected to use a frequency of 2 GHz, but the use of millimeter waves in a higher frequency band (eg, 38 GHz band) is being considered for the feeder link.

Then, the traffic packets transmitted by the terminal are forwarded to the HAPS connected to the ground station by the routing function, and sent to the Internet network. Similar processing is performed on packets sent from the Internet network to other terminals by the routing function.

NTN uses radio waves in a high frequency band, and it is assumed that the quality of wireless communication will deteriorate due to the influence of rain. For example, if there is an influence of rain, there is a risk that the service of NTN's FL (feeder link), which uses a high frequency band, may be cut off due to the rain.

Furthermore, fixed micro-wireless systems used in suburban areas with low population density and rural areas use radio waves with relatively high frequencies, and it is possible that rain on the propagation path may degrade communication quality.

Therefore, there is a need for a configuration that improves the availability of wireless communication systems by taking into account the effects of weather such as rainfall.

For example, in order to improve communication reliability in the event of a disaster, there is a known technology for monitoring and controlling by installing active and backup equipment at each base station, control station, and control station (for example, Patent Document 1).

In addition, precipitation observation using a weather radar and a rainfall prediction method using a weather radar to take into account the influence of rainfall are known (for example, Non-Patent Documents 2 and 3).

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a wireless communication system, a wireless communication method, and a wireless station that make it possible to prevent interruption of wireless communication due to the influence of weather. .

A wireless communication system according to an embodiment of the present invention includes a wireless station in which a propagation path between a node station that relays wireless communication can be affected by weather, and wherein the wireless station is equipped with a a weather radar antenna that receives a weather radar signal transmitted from a wireless station toward the node station and reflected; and a communication between the wireless station and the node station based on the weather radar signal received by the weather radar antenna. a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the rainfall predicted by the rainfall prediction unit; If the quality of wireless communication predicted by the quality prediction unit is less than a predetermined threshold, the line connecting the node station and the wireless station is connected to the node station before the line is cut off. It is characterized by comprising a switching control unit that controls switching to another line for connecting to another communication station.

Further, a wireless communication method according to an embodiment of the present invention is a wireless communication method performed by a wireless communication system having a wireless station whose propagation path between a node station that relays wireless communication can be affected by weather. The communication between the wireless station and the node station is based on the weather radar signal received by a weather radar antenna that is provided in the wireless station and receives the weather radar signal transmitted from the wireless station toward the node station and reflected. a quality prediction step of predicting the quality of wireless communication between the wireless station and the node station based on the predicted rainfall amount; and a quality prediction step of predicting the quality of wireless communication between the wireless station and the node station based on the predicted rainfall amount. is less than a predetermined threshold, the line connecting the node station and the wireless station is disconnected by another communication station connecting the node station and another communication station before the line is cut off. The method is characterized in that it includes a switching control step of controlling switching to a line.

Furthermore, the wireless station according to an embodiment of the present invention is a wireless station where a propagation path between a node station that relays wireless communication can be affected by weather, and transmits data toward the node station and is reflected. a weather radar antenna that receives a weather radar signal received by the weather radar antenna; a rainfall prediction unit that predicts a rainfall amount between the wireless station and the node station based on the weather radar signal received by the weather radar antenna; a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the amount of rainfall predicted by the rainfall amount prediction unit; and a modem that superimposes quality information indicating that the quality of wireless communication is less than a predetermined threshold on a control signal that the wireless station transmits to the node station when the quality of the wireless communication is less than a predetermined threshold. It is characterized by

According to the present invention, it is possible to prevent interruption of wireless communication due to the influence of weather.

1 is a diagram illustrating a configuration example of a wireless communication system according to an embodiment. FIG. 2 is a block diagram illustrating a configuration example and functions of a wireless station. FIG. 2 is a block diagram illustrating functions included in a control station. 1 is a flowchart illustrating an example of the operation of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of a wireless station according to an embodiment. 1 is a diagram illustrating a configuration example of a wireless communication system.

First, the background of the invention will be explained. FIG. 6 is a diagram showing a configuration example of the wireless communication system 1. As shown in FIG. As shown in FIG. 6, the wireless communication system 1 is configured such that, for example, a plurality of wireless stations 2-1 to 2-3 can each perform wireless communication via a communication satellite 3.

The radio stations 2-1 to 2-3 are, for example, earth stations each having a function as a base station, and are connected to a mobile network (not shown). The communication satellite 3 is a node station that relays wireless communication with each of the wireless stations 2-1 to 2-3.

For example, assume that in the wireless communication system 1, rain occurs between the wireless station 2-1 and the communication satellite 3. The wireless station 2-1 monitors the quality of wireless communication with the communication satellite 3 in real time, and if the quality of wireless communication deteriorates, for example, the wireless station 2-2 Perform site diversity by switching to communication.

Site diversity in the wireless communication system 1 is triggered by deterioration of actual communication quality after rainfall occurs, and switches wireless stations when, for example, the communication quality falls below a predetermined threshold. Therefore, in the wireless communication system 1, depending on the rainy situation, there is a possibility that communication may be interrupted before the wireless station is switched.

Therefore, the wireless communication system according to one embodiment predicts rainfall using weather information observed by a plurality of wireless stations each equipped with a weather radar, predicts deterioration in communication quality, and interrupts wireless communication. It is configured to improve the availability rate by switching wireless stations in advance.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 10 according to an embodiment. As shown in FIG. 1, the wireless communication system 10 includes, for example, a plurality of wireless stations 20-1 to 20-3, a communication satellite 30, and a control station 40, and constitutes an NTN. Note that when one of the plurality of configurations, such as the wireless stations 20-1 to 20-3, is not specified, it is simply abbreviated as the wireless station 20 or the like.

The wireless stations 20 are, for example, earth stations each equipped with a base station function and a weather radar, and are connected to a mobile network (not shown). The communication satellite 30 is a node station that relays wireless communication with each of the wireless stations 20 using a communication line. The control station 40 controls each device (including communication stations such as the wireless station 20) making up the wireless communication system 10 using control signals.

The wireless communication system 10 uses rainfall prediction based on meteorological data acquired by the wireless station 20-1, for example, when the wireless station 20-1 is communicating wirelessly with the wireless station 20-3 via the communication satellite 30. If it is predicted that the quality of wireless communication will be lower than a predetermined threshold (required C/N, etc.), the wireless communication route is switched.

For example, if the wireless communication system 10 predicts that the quality of wireless communication between the wireless station 20-1 and the communication satellite 30 will deteriorate due to rain (rain attenuation of radio waves) and fall below a predetermined threshold, the wireless communication system 10 -1 and the communication satellite 30 before the quality of the wireless communication between the wireless station 20-1 and the communication satellite 30 actually deteriorates and falls below a predetermined threshold. A switch is made to wireless communication between the unforeseen wireless station 20-2 and the communication satellite 30.

Next, a specific example configuration and functions of the wireless station 20 will be explained. FIG. 2 is a block diagram illustrating a configuration example and functions of the wireless station 20. As shown in FIG. 2, the radio station 20 includes, for example, a communication system including a communication antenna 21, a transmitting/receiving device 22, a modem 23, and a transmission device 24, a weather radar antenna 25, a signal processing device 26, and an analyzing device 27. It has a weather observation system.

Furthermore, the wireless station 20 is connected to the control station 40 via, for example, a mobile network 100 or another network not shown.

The communication antenna 21 is a communication antenna for performing wireless communication with the communication satellite 30. The transmitting and receiving device 22 is a device that transmits and receives signals to and from the communication satellite 30 via the communication antenna 21.

The modem 23 is a device that modulates and demodulates signals transmitted and received by the wireless station 20 and outputs the modulated signals to the transmitting/receiving device 22 (and the transmitting device 24). The modem 23 also has a function of superimposing a signal output by the analysis device 27 (for example, quality information to be described later) on a signal transmitted to the communication satellite 30 (or control station 40).

For example, if the quality of wireless communication predicted by a quality prediction unit 274 (described later) is less than a predetermined threshold, the modem 23 responds to the control signal transmitted from the wireless station 20 to the communication satellite 30 by quality information indicating that the quality of the image is less than a predetermined threshold.

The transmission device 24 is a device that is connected to the mobile network 100 and transmits and receives signals to and from the mobile network 100.

The weather radar antenna 25 transmits a weather radar signal in the direction of the communication partner (for example, toward the communication satellite 30), receives the weather radar signal reflected back from the communication satellite 30, rain clouds, and rainfall, and transmits the signal. It is output to the processing device 26.

That is, since the propagation path between the wireless station 20 and the communication satellite 30 can be affected by the weather, the weather radar antenna 25 is provided in the wireless station 20 and transmits data from the wireless station 20 to the communication satellite 30. Receive reflected weather radar signals.

The signal processing device 26 includes an extraction unit 260, performs signal processing on the weather radar signal output by the weather radar antenna 25, and outputs the signal processing result to the analysis device 27. For example, the extraction unit 260 extracts data necessary for rainfall prediction, such as radar reflection factor Z (dBZ) and rainfall intensity R (mm/h), from the weather radar signal received by the weather radar antenna 25, and analyzes the extracted data. Output to device 27.

The analysis device 27 includes, for example, a storage section 270, a rainfall prediction section 272, and a quality prediction section 274, and analyzes the data output by the signal processing device 26 using parameters such as frequency, and obtains quality information, etc., which will be described later. The analysis result (processing result) is output to the modem 23.

For example, the storage unit 270 stores and accumulates, for example, data extracted by the extraction unit 260 and information (described later) indicating the quality of wireless communication predicted by the quality prediction unit 274.

The rainfall prediction unit 272 predicts the rainfall between the wireless station 20 and the communication satellite 30 based on the weather radar signal received by the weather radar antenna 25, and sends information indicating the predicted rainfall to the quality prediction unit 274. Output for. More specifically, based on the data stored in the storage unit 270, the rainfall prediction unit 272 calculates the amount of rain between the wireless station 20 and the communication satellite 30 using a short-time rainfall prediction method using, for example, 20 minutes of data. Predict future rainfall.

The quality prediction unit 274 predicts the quality (deterioration, rainfall attenuation, etc.) of the wireless communication between the radio station 20 and the communication satellite 30 based on the parameters such as the rainfall and frequency predicted by the rainfall prediction unit 272. , and outputs information (quality information) indicating the predicted quality of wireless communication to, for example, the storage unit 270 (and modem 23).

Note that the quality information may include C/N and information indicating whether the quality of wireless communication is less than a predetermined threshold.

Then, the analysis device 27 outputs the quality information stored in the storage unit 270 to the modem 23 in response to access from the modem 23, for example.

Next, specific functions provided by the control station 40 will be explained. FIG. 3 is a block diagram illustrating functions included in the control station 40. As shown in FIG. As shown in FIG. 3, the control station 40 includes, for example, a transmitting/receiving section 41, a determining section 42, and a switching control section 43.

The transmitting/receiving unit 41 transmits and receives control signals and the like to and from each of the wireless station 20 and the communication satellite 30 by wireless communication.

The determining unit 42 determines the switching destination of the wireless station 20 based on the control signal received by the transmitting/receiving unit 41 (for example, the control signal on which quality information transmitted by the wireless station 20 is superimposed). For example, if there is a wireless station 20 whose quality of wireless communication with respect to the communication satellite 30 is less than a predetermined threshold, the determination unit 42 determines whether the quality of wireless communication with respect to the communication satellite 30 is higher than or equal to a predetermined threshold. 20 as the line switching destination, and outputs the determined result to the switching control unit 43.

When the quality of wireless communication predicted by the quality prediction unit 274 of the wireless station 20 is less than a predetermined threshold, the switching control unit 43 switches the line connecting the communication satellite 30 and the wireless station 20 to the line. Before the communication satellite 30 is cut off, control is performed via the transmitting/receiving unit 41 to switch to another line connecting the communication satellite 30 and another communication station (for example, another radio station 20).

For example, the control station 40 controls the switching control unit 43 to switch the line when the transmitting/receiving unit 41 receives the quality information superimposed by the modem 23 of the wireless station 20. Specifically, the control station 40 transmits a control signal to both the wireless station 20 whose wireless communication quality is less than the threshold value and the wireless station 20 whose wireless communication quality is equal to or higher than the threshold value.

Then, before the line between the wireless station 20 whose wireless communication quality is less than the threshold value and the communication satellite 30 is cut off, the control station 40 communicates the line with the wireless station 20 whose wireless communication quality is equal to or higher than the threshold value. Control is performed to switch to the line with the satellite 30.

Next, an example of the operation of the wireless communication system 10 will be described. FIG. 4 is a flowchart illustrating an example of the operation of the wireless communication system 10 according to one embodiment. As shown in FIG. 4, in the wireless communication system 10, the wireless station 20 transmits a weather radar signal using the weather radar antenna 25 (S100), and the weather radar antenna 25 receives the weather radar signal reflected by rain clouds and rainfall. (S102).

The signal processing device 26 performs signal processing on the weather radar signal received by the weather radar antenna 25, and outputs, for example, the data necessary for rainfall prediction extracted by the extraction unit 260 to the analysis device 27 (S104).

The analysis device 27 analyzes the data output by the signal processing device 26 (S106). Specifically, the quality prediction unit 274 predicts the quality (deterioration, etc.) of wireless communication between the wireless station 20 and the communication satellite 30 based on the rainfall predicted by the rainfall prediction unit 272. For example, the information (quality information) indicating the quality of wireless communication predicted by the quality prediction unit 274 includes information indicating whether the quality of wireless communication is less than a predetermined threshold.

Then, the analysis device 27 determines whether the wireless communication between the wireless station 20 and the communication satellite 30 is below a predetermined quality threshold based on the quality information predicted by the quality prediction unit 274 (S108). If the analysis device 27 determines that the quality of the wireless communication between the wireless station 20 and the communication satellite 30 is below the predetermined quality threshold (S108: Yes), the analysis device 27 proceeds to the process of S110, and determines that the quality of the wireless communication between the radio station 20 and the communication satellite 30 does not fall below the predetermined quality threshold. If it is determined (S108: No), the process returns to S100.

In step 110 (S110), the wireless station 20 uses the modem 23 to superimpose quality information indicating that the quality of wireless communication is less than a predetermined threshold on the transmission signal, and transmits the transmission signal with the quality information superimposed to the transmission signal. It is transmitted to the control station 40 via the satellite 30 (or directly).

In other words, the wireless station 20 performs rainfall prediction based on the weather radar signal received by the weather radar antenna 25, and when it predicts that the quality of wireless communication will fall below a predetermined threshold, the wireless station 20 superimposes quality information on the control signal and controls the transmit to station 40.

In step 112 (S112), the control station 40 switches the wireless station 20. Specifically, before the line between the wireless station 20 whose wireless communication quality is less than a threshold value and the communication satellite 30 is cut off, the control station 40 connects the line to a wireless station whose wireless communication quality is equal to or higher than the threshold value. 20 and the communication satellite 30.

In this manner, when the quality of wireless communication predicted by the quality prediction unit 274 is less than a predetermined threshold, the wireless communication system 10 changes the line connecting the communication satellite 30 and the wireless station 20 to the line. Since the communication satellite 30 is switched to another line connecting the communication satellite 30 and another communication station (for example, another radio station 20) before it is cut off, it is possible to prevent the radio communication from being cut off due to the influence of weather. .

Note that the wireless communication system 10 according to the embodiment described above has been described with reference to a case where the communication satellite 3 serving as a node station is provided, but the wireless communication system 10 may be equipped with a communication satellite other than the communication satellite 3, for example, located on the ground. It may also be a fixed micro-radio system equipped with a node station whose propagation path may be affected by the weather.

Furthermore, the wireless communication system 10 may be configured to include one or more wireless stations 20 and one or more other wireless stations 20 or communication stations that perform wired communication. Furthermore, in the wireless communication system 10, one or more wireless stations 20 may include all of the functions provided by the control station 40.

Note that the respective functions of the wireless station 20 and the control station 40 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured by a CPU, etc. The program may be configured as a program executed by a processor.

For example, the wireless station 20 and the control station 40 can be realized using a computer and a program, respectively, and the program can be recorded on a storage medium or provided through a network.

FIG. 5 is a diagram showing an example of the hardware configuration of the wireless station 20 according to an embodiment. As shown in FIG. 5, the wireless station 20 has an input section 50, an output section 51, a communication section 52, a CPU 53, a memory 54, and an HDD 55 connected to each other via a bus 56, and has a function as a computer. Furthermore, the wireless station 20 is capable of inputting and outputting data to and from a computer-readable storage medium 57.

The input unit 50 is, for example, a keyboard and a mouse. The output unit 51 is, for example, a display device such as a display. Further, the input section 50 and the output section 51 may be configured as a touch panel or the like.

The communication unit 52 is a communication interface that performs wireless communication.

The CPU 53 controls each part of the wireless station 20 and performs predetermined processing. The memory 54 and HDD 55 store data and the like.

The storage medium 57 is capable of storing programs and the like that cause the wireless station 20 to execute functions. Note that the architecture configuring the wireless station 20 is not limited to the example shown in FIG. 5. Furthermore, the control station 40 may include hardware similar to that of the wireless station 20.

DESCRIPTION OF SYMBOLS 1, 10... Wireless communication system, 2-1 to 2-3, 20-1 to 20-3... Radio station, 21... Communication antenna, 22... Transmitting/receiving device, 23... Modem , 24... Transmission device, 25... Weather radar antenna, 26... Signal processing device, 27... Analysis device, 3, 30... Communication satellite, 40... Control station, 41... - Transmission/reception section, 42... Decision section, 43... Switching control section, 50... Input section, 51... Output section, 52... Communication section, 53... CPU, 54... Memory, 55... HDD, 56... Bus, 57... Storage medium, 100... Mobile network, 260... Extraction unit, 270... Storage unit, 272... Rainfall prediction unit , 274...Quality prediction section

Claims

In a wireless communication system having a wireless station whose propagation path between a node station that relays wireless communication can be affected by weather,
a weather radar antenna provided in the wireless station and configured to receive weather radar signals transmitted from the wireless station toward the node station and reflected;
a rainfall amount prediction unit that predicts the amount of rainfall between the wireless station and the node station based on the weather radar signal received by the weather radar antenna;
a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the rainfall predicted by the rainfall prediction unit;
If the quality of wireless communication predicted by the quality prediction unit is less than a predetermined threshold, the node station may disconnect the line connecting the node station and the wireless station before the line is cut off. and a switching control unit that controls switching to another line connecting another communication station.
an extraction unit that extracts data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna;
further comprising a storage unit that stores the data extracted by the extraction unit,
The rainfall forecasting unit includes:
The wireless communication system according to claim 1, wherein the amount of rainfall between the wireless station and the node station is predicted based on the data stored in the storage unit.
further comprising a control station that controls the wireless station and the communication station,
The wireless station is
When the quality of wireless communication predicted by the quality prediction unit is less than a predetermined threshold, the quality of wireless communication is less than the predetermined threshold with respect to the control signal that the wireless station transmits to the node station. It has a modem that superimposes quality information indicating that
The control station is
The wireless communication system according to claim 1 or 2, wherein when the modem receives the superimposed quality information, the switching control unit controls to switch the line.
In a wireless communication method performed by a wireless communication system having a wireless station whose propagation path between a node station that relays wireless communication can be affected by weather,
The communication between the wireless station and the node station is based on a weather radar signal received by a weather radar antenna that is provided in the wireless station and that receives a weather radar signal transmitted from the wireless station toward the node station and reflected. a rainfall prediction step for predicting the rainfall amount between
a quality prediction step of predicting the quality of wireless communication between the wireless station and the node station based on the predicted rainfall;
If the predicted quality of wireless communication is less than a predetermined threshold, the line connecting the node station and the wireless station is connected to the node station and another communication station before the line is disconnected. and a switching control step of controlling switching to another line connecting the wireless communication method.
an extraction step of extracting data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna;
further comprising a storage step in which the storage unit stores the extracted data;
In the rainfall prediction step,
The wireless communication method according to claim 4, further comprising predicting the amount of rainfall between the wireless station and the node station based on the data stored in the storage unit.
In a wireless station where the propagation path between a node station that relays wireless communication may be affected by weather,
a weather radar antenna that transmits toward the node station and receives reflected weather radar signals;
a rainfall amount prediction unit that predicts the amount of rainfall between the wireless station and the node station based on the weather radar signal received by the weather radar antenna;
a quality prediction unit that predicts the quality of wireless communication between the wireless station and the node station based on the rainfall predicted by the rainfall prediction unit;
When the quality of wireless communication predicted by the quality prediction unit is less than a predetermined threshold, the quality of wireless communication is less than the predetermined threshold with respect to the control signal that the wireless station transmits to the node station. 1. A wireless station comprising: a modem that superimposes quality information indicating that the wireless station is a wireless station;
an extraction unit that extracts data necessary for rainfall prediction from the weather radar signal received by the weather radar antenna;
further comprising a storage unit that stores the data extracted by the extraction unit,
The rainfall forecasting unit includes:
The wireless station according to claim 6, wherein the amount of rainfall between the wireless station and the node station is predicted based on the data stored in the storage unit.
If the quality of wireless communication predicted by the quality prediction unit is less than a predetermined threshold, the node station may disconnect the line connecting the node station and the wireless station before the line is cut off. The radio station according to claim 6 or 7, further comprising: a switching control unit that performs control to switch to another line connecting the station and another communication station.